The difference between a new type aircraft and a conventional aircraft lies in that there is a transition region with a big bend angle between an aircraft nose and an aircraft fuselage on an aircraft shell of the new type aircraft. At the same time, since the current boarding bridge is designed and developed by the combination of the features of the conventional aircraft shell, when the current boarding bridge is used for the new type aircraft, a gap will formed between the shelter of the current boarding bridge and the new type aircraft shell and results in a poor sealing therebetween. In sleet weather, the sleet usually wets the passenger's clothing and baggage through the gap, and what is more, the sleet sometimes flows into the interior of the aircraft through the gap.
For overcoming the above technical problems, some manufacturers have done many attempts, for example, a Chinese Application CN200510063002.6 discloses sealing means for an aircraft passenger ramp or an aircraft boarding bridge, which comprises a bellows spanned on a connecting floor and having an open end with a flexible frame and another open end provided on a portal frame. In this patent application, the portal frame is fixed onto the ramp or the boarding bridge. The flexible frame sticks on the aircraft shell when the shelter is removed. The sealing means is also provided with an operating device for spreading and retracting the shelter. The operating device includes a driven rotatable shaft through which at least one pulling device connected to the flexible frame can be winded and unwinded. The operating device has two spaced-apart pivot arms, each comprising an upper arm and a lower arm connected to the upper arm via a hinge. The upper arm is pivotably attached to the portal frame near the roof of some shelter, and the lower arm is pivotably attached to the flexible frame. An expanding device is provided to spread the shelter. Although the sealing means may realize a perfect sealing with an entrance of the new type aircraft, the configuration of this sealing means is relative complex and its service life is relative short. In addition, after the flexible frame is coupled to the entrance of the aircraft, the gravity of the interior of the aircraft decreases due to the person or baggage leaving the aircraft, thus the entire aircraft fuselage moves upward and then the aircraft shell often squeezes or collides with the shelter. Both the lower arm and the upper arm in this patent application are rigid arms, so the acting force therebetween often results in the distortion or damage of the aircraft shell when the aircraft shell and the shelter squeeze or collide with each other. Therefore, it is necessary to modify the configuration of this kind of boarding bridge.